Financial instruments After tax (gain)/loss reclassified from accumulated other comprehensive income into income (Details) (Cash Flow Hedging, USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 29, 2015	Mar. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives qualifying as hedges, net of tax	$ 44	$ 70
Foreign Currency Forward Contract
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives qualifying as hedges, net of tax	$ 44	$ 70

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration